Coronary Artery Disease USMLE Step 1 Practice Question
A 79-year-old man with a history of hypertension presents with recurrent syncope and presyncope. Vital signs reveal BP 98/62 mmHg, HR 42 bpm, RR 16, temperature 37.2°C, and SpO2 98% on room air. Physical examination demonstrates marked bradycardia with an irregular pulse. ECG shows regular P waves at 80 bpm and regular QRS complexes at 40 bpm that are completely independent of each other. Troponin levels are normal. Which rhythm abnormality best explains these findings?
Answer choices
- AComplete heart block with AV dissociationCorrect answer
- BSick sinus syndrome
- CVentricular fibrillation
- DFirst degree AV block
- EAtrial flutter
- FThird degree AV block with ventricular escape rhythm
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